I think they can take the heat, the issue would be if you can sustain that heat all winter long and also provide strong light as needed. I remember seeing greenhouses here in the bay area, specifically for succulents. It is really sustained dry heat inside, and there is continuous fan blowing to facilitate ventilation around. Then on the conservatory in San Francisco, for the tropicals, distinct humid heat inside.
Plumeria falls in the tropical succulent aspect...so I am thinking it is good you can provide the warmth it needs, but the aspect of humidity in winter will be very dicey, so be careful they do not get fungal issues when you open up the windows and cold air touches them. So easy to invite black rot once they get a touch of cold air.
